Slovenia says it is considering building a border fence to help stem a record influx of migrants and refugees, as thousands more people arrived from Croatia on Friday (local time).
Prime Minister Miro Cerar said he hoped a mini-EU summit with Balkan and central European leaders on Sunday would help bring solutions to the crisis, but he has not ruled out a barrier along the 670-kilometre frontier with Croatia.
"We are considering that option too but at this moment ... we are still looking for a European option," Cerar told state TV late on Thursday.
Slovenia has become the main entry point into the European Union's passport-free Schengen zone after Hungary sealed its southern borders with razor-wire fences to stop migrants trying to reach northern Europe before winter sets in.
Ljubljana has asked Brussels for €140 million, in addition to police back-up and logistical support.
"If on Sunday we do not get sufficient [grounds for hope], if we see there is no will for collaboration, then all possibilities will be available, seeing as we will have been left alone," Cerar said.
But he stressed he saw the fence as a last resort.
More than 47,500 people have entered the small nation of two million people since October 17, when Budapest shut its frontier with Croatia, barely a month after also closing its Serbian border.
Most of the migrants, mainly fleeing violence in Syria, Iraq and Afghanistan, want to get to Germany, the EU's economic powerhouse.
About 14,000 were waiting in Slovenian refugee camps and registration centres on Friday morning, hoping to continue to neighbouring Austria whose Spielfeld border camp was also bursting with new arrivals.
Austrian Foreign Minister Sebastian Kurz warned on Friday the "surge into Europe" had become too big, adding bloc members had a responsibility to protect their borders.
Border fences in Hungary and other EU countries had proven effective in tackling the crisis, Kurz said.
"The question is whether you want them or not," Kurz told public broadcaster Oe1.
His comments echo those of Interior Minister Johanna Mikl-Leitner who on Thursday announced it was time for the EU to "build fortress Europe", after she had visited the Spielfeld checkpoint.
About 7000 migrants have crossed into Austria from Slovenia since Thursday, with about 4500 still stranded at Spielfeld on Friday morning, police said.